Description of problem:
ipa help config-mod doesnt have all options documented

While trying to do ipa migrate-ds, It fails with an error.

# ipa migrate-ds ldap://rhds9-1.gsslab.pnq.redhat.com:389
Password:
-----------
migrate-ds:
-----------
Migration mode is disabled. Use 'ipa config-mod' to enable it.

but ipa config-mod doesnt have any documentation about Migration option.

# ipa help config-mod |grep -i migrate
-- No Output --

Below commands works well, but this option should be documented.
# ipa config-mod --enable-migration=TRUE


Additional info:
It is properly documented in https://access.redhat.com/documentation/en-US/Red_
Hat_Enterprise_Linux/7/html/Linux_Domain_Identity_Authentication_and_Policy_Gui
de/Migrating_from_a_Directory_Server_to_IPA-Performing_a_Client_based_Migration
.html

I think it should be documented in help page of ipa config-mod